First of all, I'm not wanting to build the motor right now, I'm just having a bit of a discussion. Your suggestion of building a "Cleaver" is a good one, but I think the 400 block is heavier, and is built to handle the long stroke. It seams in this case that one might be better off using the motor that already has 400 cubes rather than building one yourself. And technically, a cleve. headed 400 would be a factory "mystery motor" You also wouldn't have to invest in the stroker crank, rods and any mods you would encounter in the installation.